WO-99/05244, WO-99/05082 and U.S. Pat. No. 6,111,158 relate to alkylarylsulfonate surfactants of which the alkyl groups are branched. Sources of the alkyl groups are for example paraffins with limited branching obtained by delinearization of linear paraffins.
U.S. Pat. No. 5,849,960 relates to surfactant sulfates based on branched alcohols. The branched alcohols in question have an average number of branches per molecule chain of at least 0.5. The branching comprises not only methyl branching but also ethyl branches, whilst the occurrence of longer branching is not excluded. The branched alcohols are made from branched olefins, which are made by skeletally isomerizing linear olefins.
The market always asks for improvements in the performance of existing detergent formulations, inter alia by improving the surfactants present in the detergent formulations. For example, the laundry market asks for improvements in the surfactants' biodegradability, their cold water solubility and their cold water detergency. At least an improvement is sought in the balance of the properties. By the terminology “an improvement in the balance of the properties” it is meant that at least one property is improved, whilst at least one of the other properties is not deteriorated.
The present invention seeks to provide improvements in the performance of the known alkylarylsulfonate surfactants, or at least in an improvement in the balance of their performance properties. Relevant performance properties are biodegradability, cold water solubility and cold water detergency, for example cold water detergency in water of low hardness and in water of high hardness. Other relevant performance properties are the compatibility of the alkylarylsulfonate surfactants with other components present in detergent formulations, as described hereinafter, in particular, the compatibility with enzymes, i.e. the inability of the alkylarylsulfonate surfactants to denature enzymes during storage in an aqueous medium. Again other relevant performance properties, in particular for personal care applications, are mildness to the skin and to the eyes and the ability of high foaming, preferably providing foam with a fine structure of the foam cells. Further, an improved performance is sought as a chemical for enhanced oil recovery applications and for the removal of oil spillage, viz. an improved ability to emulsify oil/water and oil/brine systems and to stabilize emulsions of oil and water or brine, in particular at high temperature. Independently, the present invention seeks to provide a method for the manufacture of alkylarylsulfonate surfactants which is more versatile and economically more attractive than the known methods.